83 lines
2.2 KiB
Nim
83 lines
2.2 KiB
Nim
import
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./datatypes, ./uint_bitwise_ops, ./bitops2_priv, ./int_bitwise_ops,
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./compiletime_cast
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export compiletime_cast
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func getByte*(x: SomeInteger, pos: int): byte {.compileTime.} =
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type DT = type x
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when bitsof(DT) == 8:
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cast[byte](x)
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else:
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byte((x shr (pos * 8)) and 0xFF.DT)
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func getByte*(x: UintImpl | IntImpl, pos: int): byte {.compileTime.} =
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type DT = type x.leastSignificantWord
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when bitsof(DT) == 8:
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cast[byte](x.leastSignificantWord)
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else:
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byte((x shr (pos * 8)).leastSignificantWord and 0xFF.DT)
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proc setByte*(x: var SomeInteger, pos: int, b: byte) {.compileTime.} =
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type DT = type x
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x = x or (DT(b) shl (pos*8))
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type SomeIntImpl = UintImpl | IntImpl
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func setByte*(x: var SomeIntImpl, pos: int, b: byte) {.compileTime.} =
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proc putFirstByte(x: var SomeInteger, b: byte) =
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type DT = type x
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x = x or b.DT
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proc putFirstByte(x: var UintImpl, b: byte) =
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putFirstByte(x.lo, b)
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var cx: type x
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cx.putFirstByte(b)
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x = x or (cx shl (pos*8))
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func copyToArray*(ret: var openArray[byte], x: UintImpl) {.compileTime.} =
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const size = bitsof(x) div 8
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doAssert ret.len >= size
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for i in 0 ..< size:
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ret[i] = x.getByte(i)
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func copyFromArray*(x: var UintImpl, data: openArray[byte]) {.compileTime.} =
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const size = bitsof(x) div 8
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doAssert data.len >= size
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for i in 0 ..< size:
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x.setByte(i, data[i])
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func copyFromArray*(x: var SomeInteger, data: openArray[byte]) {.compileTime.} =
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const size = bitsof(x) div 8
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doAssert data.len >= size
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for i in 0 ..< size:
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x.setByte(i, data[i])
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template vmIntCast*[T](data: SomeInteger): T =
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type DT = type data
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const
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bits = bitsof(T)
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DTbits = bitsof(DT)
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# we use esoteric type juggling here to trick the Nim VM
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when bits == 64:
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when DTbits == 64:
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cast[T](data)
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else:
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cast[T](uint64(data and DT(0xFFFFFFFF_FFFFFFFF)))
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elif bits == 32:
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when DTbits == 32:
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cast[T](data)
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else:
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cast[T](uint32(data and DT(0xFFFFFFFF)))
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elif bits == 16:
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when DTbits == 16:
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cast[T](data)
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else:
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cast[T](uint16(data and DT(0xFFFF)))
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else:
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when DTBits == 8:
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cast[T](data)
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else:
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cast[T](uint8(data and DT(0xFF)))
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